Safety problem?

Hello I have a converted Saiga .308 with a dinzag modified g2 trigger in it. The trigger is very light at about 2.5lbs and then there is a crisp break. I found when i take the trigger to the crisp break leave it there and then try to put the safety up the weapon will engage the hammer. Is this normal? Also there is a thin metal piece that looks like it goes onto the end of the gas tube (reciever end) but when i try to put it on the gas lever wont fully set down, without the piece it seems loose It was in a bag of parts i had after i sanded the rifle for a coating.